After promising preliminary results were obtained from energy loss and x-ray elemental maps with the Hitachi 200 keV analytical TEM-STEM, it was necessary to improve the performance and stability of the system to make applications to biological problems possible. Such improvements have led to increased sensitivity and improved ease of operation. A new high voltage power supply has been incorporated into the energy loss spectrometer deflection plates so that a 100eV range of energy loss can be covered in a single image. New data acquisition software, run by the LSI 11-23 satellite computer, has been written to compensate for spectrometer drift by "locking on" to the carbon edge in the energy loss spectrum. This enables images to be acquired over periods of one hour or more. Extensive software (K.E. Gorlen, DCRT) has been developed for the automation of data acquisition incorporating video display menus run from the DEC PDP 11/60 computer. Various parameters required for data acquisition are entered into "forms" so that the operator always has an updated list of values. Additional software has been written for use with the DeAnza image processor system. This allows the user to display and operate on the images using a "digitizing tablet". Operations such as obtaining histograms, enhancing constrast or scrolling may be achieved very rapidly in this way. It is now possible to acquire not only the number of core edge counts at each pixel but also the parameters for the background fit. This allows more sophisticated data analysis to be carried out with concomitant reduction in noise and higher sensitivity. Improvements have also been made in the energy dispersive X-ray imaging. A digital filter is applied to the spectrum and the computer sums the filtered counts in each peak of interest at each pixel to determine the intensity. Artifacts due to mass thickness can be removed in this way. Apart from these software developments, improvements in the microscope are also in progress. A cryotransfer specimen holder (purchased from Gatan) should allow samples to be maintained at close to liquid nitrogen temperature with high mechnical stability. Experiments on frozen hydrated thin sections are proposed to study the distribution of low atomic number elements in cells.